1. Field of the Invention
The present invention relates to a seat belt for motor vehicle and more particularly, to a buffer device for a vehicle seat belt.
2. Description of the Related Art
In order to protect passengers in a motor vehicle against injury upon an impact, safety means such as pretensioner car body, seat belts, air bags, and etc. may be provided in the motor vehicle. Seat belts are popularly used in motor vehicles to secure passengers to the seats. A seat belt in a motor vehicle works to provide a first line of protection. A vehicle seat belt generally has three fixed points respectively disposed at two sides beneath the seat and a top side above the passenger's shoulders. After fixation to the three points, the seat belt can be extended over the front side of the pelvis and the front side of the chest of the passenger. The seat belt secures the passenger to the seat against the inertia force of the motor vehicle upon an impact force, preventing the passenger from hitting the windshield glass or something in front of the seat.
However, if the motor vehicle is crushed by another motor vehicle or hits another motor vehicle when running at a high speed, a high inertia force will be produced, and the passenger will cause a relatively greater impact force to the seat belt, causing the seat belt to produce a relatively greater reactive force to the passenger. In this case, the seat belt will give a high pressure to the passenger to prohibit the passenger from falling out of the seat. This high pressure may result in an injury to the passenger.
Therefore, it is desirable to provide a buffer device for vehicle seat belt that eliminates the aforesaid problem.